From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8BA58C433DF for ; Thu, 30 Jul 2020 10:08:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6930421883 for ; Thu, 30 Jul 2020 10:08:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728858AbgG3KI2 (ORCPT ); Thu, 30 Jul 2020 06:08:28 -0400 Received: from mail1.windriver.com ([147.11.146.13]:38298 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726273AbgG3KI1 (ORCPT ); Thu, 30 Jul 2020 06:08:27 -0400 Received: from ALA-HCB.corp.ad.wrs.com (ala-hcb.corp.ad.wrs.com [147.11.189.41]) by mail1.windriver.com (8.15.2/8.15.2) with ESMTPS id 06UA89XB019930 (version=TLSv1 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Thu, 30 Jul 2020 03:08:09 -0700 (PDT) Received: from pek-lpg-core1-vm1.wrs.com (128.224.156.106) by ALA-HCB.corp.ad.wrs.com (147.11.189.41) with Microsoft SMTP Server id 14.3.487.0; Thu, 30 Jul 2020 03:07:48 -0700 From: To: , , , , CC: , Subject: [PATCH v3] mm/slab.c: add node spinlock protect in __cache_free_alien Date: Thu, 30 Jul 2020 18:19:34 +0800 Message-ID: <20200730101934.38343-1-qiang.zhang@windriver.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhang Qiang for example: node0 cpu0 cpu1 slab_dead_cpu >mutex_lock(&slab_mutex) >cpuup_canceled slab_dead_cpu >mask = cpumask_of_node(node) >mutex_lock(&slab_mutex) >n = get_node(cachep0, node0) >spin_lock_irq(n&->list_lock) >if (!cpumask_empty(mask)) == true >spin_unlock_irq(&n->list_lock) >goto free_slab .... >mutex_unlock(&slab_mutex) .... >cpuup_canceled >mask = cpumask_of_node(node) kmem_cache_free(cachep0 ) >n = get_node(cachep0, node0) >__cache_free_alien(cachep0 ) >spin_lock_irq(n&->list_lock) >n = get_node(cachep0, node0) >if (!cpumask_empty(mask)) == false >if (n->alien && n->alien[page_node]) >alien = n->alien >alien = n->alien[page_node] >n->alien = NULL >.... >spin_unlock_irq(&n->list_lock) >.... Due to multiple cpu offline, The same cache in a node may be operated in parallel,the "n->alien" should be protect. Fixes: 6731d4f12315 ("slab: Convert to hotplug state machine") Signed-off-by: Zhang Qiang --- v1->v2->v3: change submission information and fixes tags. mm/slab.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index a89633603b2d..290523c90b4e 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -759,8 +759,10 @@ static int __cache_free_alien(struct kmem_cache *cachep, void *objp, n = get_node(cachep, node); STATS_INC_NODEFREES(cachep); + spin_lock(&n->list_lock); if (n->alien && n->alien[page_node]) { alien = n->alien[page_node]; + spin_unlock(&n->list_lock); ac = &alien->ac; spin_lock(&alien->lock); if (unlikely(ac->avail == ac->limit)) { @@ -769,14 +771,15 @@ static int __cache_free_alien(struct kmem_cache *cachep, void *objp, } ac->entry[ac->avail++] = objp; spin_unlock(&alien->lock); - slabs_destroy(cachep, &list); } else { + spin_unlock(&n->list_lock); n = get_node(cachep, page_node); spin_lock(&n->list_lock); free_block(cachep, &objp, 1, page_node, &list); spin_unlock(&n->list_lock); - slabs_destroy(cachep, &list); } + + slabs_destroy(cachep, &list); return 1; } -- 2.26.2